The HotBin: Aerobic hot composter review

It's normally around Christmas time - when other people (some may call them 'normal') turn their thoughts to presents, festive nights out* and how long it takes to defrost a turkey -  that I start getting twitchy about my kitchen caddy.

With the potato peelings, sprout snubs and pouring in daily, the caddy seems to be full to overflowing (not a good look) every time I turn around. And yet my composters - the two "beehives" and two wormeries - are also stuffed full of not-very-decomposed kitchen waste already. Yes, I can dig a bean trench, but if the grounds frozen or I am feeling sluggish, that may not happen.

So when the chance to try out a new compost bin that promised to chomp my kitchen waste and garden waste and aerobically compost it at 60C, even in the depths of winter, I jumped at it.**

The HotBin's claims include that it "recycles more types of household food waste, generates rich compost more quickly and delivers efficient hot aerobic composting". So we're talking about composting at a temperature of at least 60C, and the ability to add garden waste including weed seeds, and kitchen waste of all kinds including meat and fish. Yes please!

About a month in to my trial, it's proven a bit of a tease to get the HotBin "up to speed".The setup instructions recommend adding a starter layer of compost 30cm deep to start with: added to that, I primed the beast with regular additions of all and sundry from the now much-relieved kitchen caddy. Still I only managed to get the temperature up to 60C once (at least I managed to get a picture of the moment, above) usually stalling at a steamy but not quite hot enough 40-50C. I did try the recommended 'kickstarter', adding a plastic bottle full of boiling water nestled within the pile, but this didn't seem to work, and repeatedly boiling the kettle didn't seem particularly green. I think I know what some of the problems were:

1. I do not, and never will, chop up my kitchen waste. If an apple's whole, it goes in whole. The HotBin does come with a handy poker/rake device which I did use to break up a few bigger lumps once they've softened, but nevertheless I suspect this slows things down a little.

2. Being a curious type, I lifted off the 'access hatch' at the bottom to see what was going on down below and had trouble getting it back in position tightly - I suspect cold air may be leaking in that way.

And bear in mind that the outside temperature was dropping to 0C and below at this point, so compared to my other compost heaps, which were icy to say the least, I should be impressed by its performance. This is only my early-days findings - I'll report back again in a month or two once I have conmposted some more. But to summarise so far:

HotBin pros

• Can take all kitchen and garden waste: a huge bonus. My black bin waste has dropped as a result and I should be making more compost than before.
• Produces compost more quickly than conventional garden heaps (32 times more quickly, according to the marketing bumph): again, a huge plus if it's true - and so far, without quite reaching the heady heights of a constant 60C temperature, the pile sinks very fast. In smaller families may have to beg waste from neighbours to feed their HotBin.
• Is wheelie-bin sized and compact (takes 200l of waste) and not as hideous-looking as some other composters (see point below about siting though).
• The lid stays up when you lift it. Let me repeat that: THE LID STAYS UP! This, my friends, is compost heap progress.
• The HotBin setup kit includes a thermometer on a stick, which is very useful for checking how hot things are. If you're a bit sad like me you may find yourself becoming a bit addicted to checking the temperature.

HotBin cons

• I am not entirely convinced of the long-term durablility of the HotBin's walls, they look as if they could easily be damaged by a wayward trowel. In fact mine already had a ding in it when it arrived, which you can see in the photo (right).
• Though I could theoretically keep it on the patio outside the back door, as it's pictured here, there does seem to be some liquid coming from the little grille right at the bottom - possibly not very good for my stone, so I have moved it onto grass.
• Price - how many of us can afford (or want to) spend £138 on a new compost bin, even if it is a whizzy one?
• The hatch - I had trouble fitting it back in place snugly. If you are batch composting and emptying the whole thing it shouldn't be a problem, but if (like most of us) you want to remove some compost and leave the rest to mature, it's hard to get a proper fit and avoid compost jamming the entrance.

* I don't do festive nights out, I have two small children so prefer to get drunk on Stone's Ginger Wine in front of the Come Dine With Me Christmas special.

**Disclosure: As per the Guardian's editorial code I can't accept gifts so this composter will be going back to the people at HotBin to be passed on to another tester when I have finished with it.

Comments

[Dawn Isaac]

I would be interested to know how hot a 1m x 1m x 1m compost bin would get up to without the need for the HotBin technology (well, I say intersted, but, you know, not interested enough to get off my backside and check when it's freezing outside). The only test I currently run is how often the cat sits on top of the pile as this is an indication that it's the warmest spot available (the answer: quite often - scientific, huh?).

[Tony Callaghan]

With a bit of physics (Newton's law of cooling), a bit of biology (rate of biochemical reactions) we can tell you the answer without leaving the comfort of our chair!

A properly maintained 1m3 heap can hit 60C - but it will only say hot in the centre. The average UK home produces 500 litres of food waste a YEAR. The 1m3 heap needs 1000 litres to start AND a big dollop more each and every week to keep it going at 60C.

Cats love a warm spot - but warm not hot. I'm dubious it would sit on a surface at 40C (baking desert sun) for long and certainly not on a 60C surface at all - it would scold itself.

[AllotmentBlog]

This is interesting - my query is about durability, I suppose. Over the years we've tried a number of hot composting systems, and if you can get the temperature up and keep it up, they work. The problems, for us, have always been in the equipment: remaking a cone composter into a hot composter with bubble-wrap and binbags works brilliantly for a year, and then you find you have a cone-shaped snail incubater as they wheedle their way into the crevices of the wrapping and breed happily. We also had an insulated compost bin supplied and it just got taken apart by the weather: it cracked in summer and cracked in sub zero temperatures and the insulation flaked off and if you hit it with the wheelbarrow it dented, and then the rain settled in the dent and froze and cracked the surface ... it's a lovely idea but we're just not careful enough, I fear.